Answer
$(x_1,x_2,x_3)=(0,0,0)$
Work Step by Step
Consider $4x_3=0 \implies x_3=0$
and $-5x_2+2x_3=0 \implies -5x_2+2(0)=0$
or, $x_2=0$
Now, $x_1+2x_2+3x_3=0 \implies x_1+2(0)+3(0)=0$
or, $x_1=0$
Our result is : $(x_1,x_2,x_3)=(0,0,0)$